A router is a tool, especially used in the woodworking industry, used for milling out (hollow out) an area in the face of a piece of material (work piece). Usually the material is wood or metal, but applying the router to other types of materials is also possible. There are several types of routers. Nowadays, most common types are spindle type routers (spindle routers), where a router bit is mounted onto a rotatable spindle of an electric motor.
A typical router set-up includes a frame for supporting the router table. The piece of material to be machined is supported by the router table. The router table has an opening through which a bit protrudes for machining the material. Different bit sizes and shapes can be used, and the bit is easily exchangeable. The bit is engaged by a collet provided with a clamping mechanism such as a number of clamps or jaws. The collet is part of a rotatable spindle that is connected to a motor drive for rotation. The router collet (and router bit mounted in the mouth of the collet) can be rotated around an axis perpendicular to the router table. Sometimes the collet may be able to move with respect to the router table, for example, along the axis of rotation by a depth adjustment tool. In this case, the shape of the cut that is created is determined by the size and shape of the bit (cutter) held in the collet and the height of the bit relative to the work piece. The bit may machine a work piece from the bottom of the piece by positioning the work piece over the opening in the router table and the bit to e.g. form a shaped groove or a shaped recess in the work piece. The bit may machine the work piece from a side by positioning the work piece adjacent to the opening in the router table with the router bit acting on the side of the work piece, to e.g. form a tapered side, or to form a groove in the side of the work piece.
A typical router system also includes a router fence. The router fence is placed on top of the table and is used as a stop along which the work piece can be guided during the machining thereof to ensure that proper parts of the work piece are cut away. The router fence is used as a directional tool during the processing of the work piece.
End grain wood, being the narrower side (the end) of a board, is difficult to guide along (and square to) the router fence of the router table without a considerable risk of it being pulled into the router bit which may damage the work piece and/or which may cause a hazardous situation. This is in contrast to guiding the long grain side of a board that can slide easily along the router fence, without a serious risk of it being pulled into the router bit.
In order to provide an improved guidance and to reduce the risk of being pulled into the router bit, the concept of a holding device, also referred to as coping sled or coping jig, used for routing the short end of a work piece (usually the end grain) has been developed in the woodworking industry. To hold the work piece firmly, but in such manner that it can still be moved parallel to the router fence for its edge forming, is a challenge that existing coping sleds have attempted to solve by mounting the clamping devices on a carrier board, exercising downward pressure. This carrier board effectively increases the height of the router table, so that it has to pass underneath the router bit. Consequently the router and/or the router bit have to be mounted higher to compensate for the thickness of the carrier plate.
Furthermore, this arrangement prevents the use of coping sleds vertically, as described above, because they do not have their own fence for keeping the coping sled safely positioned, and the carrier plate cannot ride behind the router bit in this position, as the carrier plate will be in between the router bit and the work piece. This is particularly prejudicial if a particular router bit set-up should not be disturbed between horizontal and vertical operations.
A further drawback of coping sleds using a carrier plate is the risk of deformation of that carrier plate, notably bending up, if more than a minimal clamping force is used to secure the work piece, compromising the integrity of the routing operation.